The present invention relates to a fluid dispenser for dispensing fluid in liquid or powder form, the fluid dispenser comprising a reservoir provided with at least one deformable actuating wall and with a dispensing orifice. Thus, by pressing the actuating wall, it is possible to reduce the internal volume of the reservoir so as to deliver the fluid through the dispensing orifice. That type of dispenser can be used in the fields of perfumes, cosmetics, or indeed pharmaceuticals for dispensing liquids or powders.
In the prior art, numerous dispensers of that type exist that use the deformation capacity of a portion of the reservoir to put the fluid that it contains under pressure so as to deliver it through the dispensing orifice. For example, reference can be made to Document FR 2 791 645 which discloses a dispenser in the form of two flexible sheets that are bonded together all the way around their peripheries so as to define a reservoir. A rigid dispensing part is preferably inserted between the two sheets: that dispensing part advantageously forms the dispensing orifice. In addition, a spring may be disposed between the two sheets so as to perform a resilient return function. In that document, provision is even made to close off the dispensing orifice while the spring is compressed to its maximum extent. Thus, a fluid dispenser is obtained that is particularly flat and that can, for example, be included in a magazine by way of a free sample.
The drawback with that prior art dispenser lies in the fact that the spring is held compressed to its maximum extent for a relatively long period, i.e. from being manufactured to being used. Experience shows that a spring made of a plastics material no longer relaxes after it has been held for a certain length of time in its maximum compressed state. This is because plastics material tends to creep over time. Alternatively, if the spring is made of metal, then the fluid to be dispensed remains in contact with the metal for a long period of time. In some cases, that can be inconvenient, or even harmful, depending on the fluid to be dispensed. There is therefore a real problem with the return spring of that type of dispenser.
An object of the present invention is to remedy the above-mentioned drawback of the prior art by defining a dispenser that is relatively flat and whose spring means are not compressed or at least are compressed only very slightly when pressure is exerted on the dispenser while lying flat. For example, the dispenser must be capable of being included in magazines without any risk of compressing the spring means too strongly.
To achieve this object, the present invention makes provision for the fluid dispenser to further comprise a body defining a frame having a thickness defined to determine a defined inscribed volume, said actuating wall extending over said frame and being deformable so as to reduce the volume of the reservoir and so as to penetrate into the inscribed volume. Thus, even if the dispenser is included between two substantially plane surfaces and pressure is exerted on said surfaces, there is no risk of reducing the working volume of the reservoir to smaller than the inscribed volume defined by the thickness of the frame.
The present invention provides that the dispenser is provided with return spring means for urging the actuating wall into a rest configuration defining the maximum volume of the reservoir. It is then advantageous for the spring means to be formed integrally by the body which already forms the body. For example, the body may be made of a plastics material.
According to an advantageous characteristic of the invention, the spring means extend inside said frame. In the rest position, the spring means may even extend inside said inscribed volume. In a variant, in the rest position, the spring means extend outside said inscribed volume. When the spring means extend inside the inscribed volume, and when in the rest position, the spring means do not stress the actuating wall(s). It is only after the walls are pressed that the spring means return the actuating wall(s) to the rest position. Conversely, when the spring means extend outside the inscribed volume, they stress the actuating walls, even when in the rest position. This results in the actuating wall bulging where the spring means are in contact with the wall.
In a practical embodiment, the spring means may comprise at least one flexible blade which extends across said frame. For example, the frame may have a constant thickness of approximately in the range 2 millimeters to 4 millimeters.
In a practical embodiment, the dispenser may further comprise two actuating walls defined by two flexible sheets fixed in leaktight manner on either side of said frame.
According to another characteristic, the frame is substantially non-deformable. Thus, the return spring function is performed entirely by the spring means, and not by the frame.
In a practical embodiment, the frame is substantially in the form of a ring.
According to a characteristic, the dispensing orifice is formed by the frame, advantageously in its peripheral surface.